1. Technical Field
The present invention relates to a dual polarized antenna and, more particularly, to a versatile antenna system capable of receiving vertical signals and horizontal signals simultaneously.
2. Description of Related Art
So-called MIMO (Multiple Input Multiple Output) involves receiving or transmitting wireless network signals by means of multiple antennas and channels with enhanced transmission efficiency. Such a MIMO system is typically equipped with plural (mostly three) sets of antennas at both the transmitter and the receiver thereof for overcoming the problem of the reduced transmission efficiency during receiving or transmitting. More particularly, MIMO technology segments digital data multiply and implements multiple antennas to enhance data transmission efficiency when receiving or transmitting the processed signals simultaneously.
Since MIMO technology segments digital data and transmits the same through multipath transmission, it facilitates relaxing single-way signal flow and extending the transmission distance as well as the reception range of antennas. Hence, MIMO is generally applied to current wireless network apparatuses where high speed and long distance of transmission are desired.
As a contemporary wireless router product with MIMO technology typically comprises three sets of half wave antennas, which are aligned in to a row or a triangle with a particular interval mutually, however, those antennas can only be arranged manually to an alternative polarization direction. For instance, when a vertical polarization direction of an antenna is demanded, the antenna has to be settled vertically to the horizontal; and when a horizontal polarization direction is needed, it has to parallel to the horizontal. Thus, each antenna can only achieve single polarization. This may in turn incur receiving dead points and causes the antenna to be disadvantageously inflexible between transmitting and receiving functions according to the surrounding signal strength.
On the other hand, a Smart Antenna, according to the surrounding signal strength, allows an antenna performing optimal reception to be switched to act as the receiver. Such a system generally comprises two sets of half wave antennas and a switch that is provided for each antenna to couple with the signal transmitter/receiver. When there are signals to be transmitted, both the antennas are implemented simultaneously (both the antennas work as transmitters). Alternatively, when there are signals to be received, the system first compares the received noise levels of both antennas to find the one that is receiving signals stronger and picks it as the receiver through the switch for optimum wireless signal transmission and reception.
Accordingly, a need exists for an antenna that integrates the advantages of the discussed MIMO technology and a Smart Antenna.